How to save everyone in the ME2 suicide mission
Hopefully, if you've completed everyone's loyalty mission and made all of the right choices, you have a fully loyal crew going in to the suicide mission.
Here's how to complete it with no casualties providing everyone is loyal. It also has the added bonus of having some call-backs in ME3 and exclusive dialogue to ME2.
PART ONE
Tech Specialist: TaliĀ
Second Team Leader: Garrus
PART TWO
Biotic Specialist: Jack
Second Team Leader: Garrus
Escort: Mordin
PART THREE
Your Squad: Miranda and your Love Interest if they are available. If they're not, take Garrus.
That should get you the achievement and save everyone on your crew.